Antihypertensives Flashcards
How do diuretics decrease BP?
Cause diuresis which reduces plasma and stroke volume causing a decrease in cardiac output and blood pressure. Most common adverse effect is hypokalemia
Describe the use of hydrocholorthiazide (HCTZ) as a antihypertensive agent
First line diuretic. Inhibits NaCl reabsorption in the distal convoluted tubule of the nephron. Patients allergic to sulfa may be allergic to HCTZ. Ineffective if creatinine >2.5
Describe the use of loop diuretics as antihypertensive agents
Selectively inhibit NaCl reabsorption in the thick ascending limb of the loop of Henle. Stronger incidence of hypokalemia. Reserve for patients with chronic renal insufficiency
Name the four loop diuretics
Furosemide (Lasix). Torsemide (Demedex). Bumetanide (Bumex). Metolazone (Zaroxolyn)
Describe the use of K+ sparing diuretics
Antagonize the effects of aldosterone at the late distal and cortical collecting tubule in the nephron. Weak when used alone, but spare K+ and Magnesium loss
Name the three K+ sparing diuretics
Aldactone (Spironolactone).Midamor (Amiloride). Dyrenium (Triamterene)
How do beta blockers reduce BP?
Reduce heart rate and Cardiac Output (Antagonize the effect of catecholamine’s at adrenoceptors.
Decrease sympathetic drive). Decrease renin release. Are cardioprotective
Define cardioprotective
Negative inotropic effect (decrease 02 consumption by the heart by decreasing the force of the contraction). Negative chronotropic effect (decrease heart rate)
Name the four B1 selective beta blockers
Metopropol (Lopressor, Toprol XL). Atenolol (Tenormin). Bisopropol (Zebeta). Acebutolol (Sectrol)
Name the four nonselective beta blockers
Propanolol (Inderal). Sotalol (Betapace). Timolol (Blocadren)
Name the two combination Beta and alpha 1 blockers
Carvedilol (Coreg). Labetolol (Trandate)
What are adverse effects to beta blockers?
Bradycardia, Heart Failure, Bronchospasm (use B1 selective for asthmatics), mask hypoglycemia, lower HDLs, hypotension
What are side effects of beta blockers?
Impotence, Depression, Sedation, Fatigue, Reduced ability to exercise, Cold extremities
How does hypoglycemia occur with use of beta blockers?
β2 adrenoceptors normally stimulate hepatic glycogen breakdown (glycogenolysis) and pancreatic release of glucagon to increase plasma glucose. blocking β2-adrenoceptors lowers plasma glucose. beta blockers mask the typical sympathetic responses to hypoglycemia…..tachycardia and tremors
What drugs interact with beta blockers?
NSAIDS-blunt effect of beta blockers. Epinephrine-causes severe hypertension in presence of beta-blockade. Calcium channel blockers: Conduction effects on heart are additive with beta blockers
How do ACE inhibitors lower BP?
Block the conversion of angiotensin I to angiotensin II, leading to artery and vein dilatation reducing arterial pressure, preload and afterload
How are ACE inhibitors renal and cardioprotective?
decrease proteinuria and chronic renal failure in diabetics. Inhibits cardiac and vascular remodeling associated with chronic hypertension, heart failure and MI
Name the six ACE inhibitors
Captopril (Capoten). Lisinopril (Zestril). Enalapril (Vasotec). Benazpril (Lotensin). Ramipril (Altace). Quinapril (Accupril)
For what disease conditions are ACE inhibitors considered to be the first drug of choice to treat HTN?
DM, CHF, chronic kidney failure, MI that causes systolic dysfunction
What are contraindications to ACE inhibitors?
bilateral Renal Artery Stenosis, Should not be given with K+ sparing diuretics, pregnancy
Describe angiotensin receptor blockers as antihypertensives
Blockade angiotensin II receptors. Cardioprotective and renal protective. Side effect profile similar to ACE except decreased incidence of cough. CI in pregnancy and renal stenosis
Name the five ARBs
Irbesartan (Avapro). Candesartan (Atacand). Losartan (Cozaar). Valsartan (Diovan). Olmesartan Medoxomil (Benicar)
How do calcium channel blockers reduce BP?
Dilate peripheral arterioles by blocking the influx of calcium into arterial smooth muscle cells. This reduces PVR and BP. Decreases contractile force and myocardial O2 requirements.
Name the six dihyropyridines
Amlodipine (Norvasc), Felodipine (Plendil), Nicardipine (Cardene), Nifedipine (Procardia), Isradipine (Dynacirc), Nimodipine (Nimotop)
What are the adverse effects of dihyropyridines?
reflex tachycardia, flushing, headache, excessive hypotension, edema
What are the two non-dihyropyridines?
Verapamil (Calan, Isoptin) and Diltiazem (Cardizem). Also used to treat dysrhythmias, angina, headaches
What are the adverse effects of non-dihyropyridines?
excessive bradycardia, impaired electrical conduction (atrioventricular nodal block), depressed contractility, concern with beta blockers, Shouldn’t be given with heart block and systolic failure.
How do alpha 1 blockers reduce BP?
Block alpha receptors in small arterioles and venules. Reduce arterial pressure by dilation. Lower PVR
For what patient populations are alpha 1 blockers reserved for?
Use in low doses should be reserved for unique cases such as men with BPH as data does not suggest protection against cardiovascular events.
Name the three alpha 1 blockers
Prazosin (Minipress), Terazosin (Hytrin), Doxazosin (Cardura)
How do alpha 2 receptor agonists lower BP?
has specificity towards the presynaptic alpha 2 receptors in the vasomotor center in the CNS.
Decrease in sympathetic outflow from the vasomotor center = decreased vasoconstriction
What are the two alpha 2 receptor agonist and their uses?
Clonidine (Catapres): useful as a second or third line drug choice for lowering blood pressure when other anti-hypertensive medications have failed.
Methyldopa (Aldomet): Frequently used in pregnancy
How are vasodilators used as antihypertensive agents?
Cause direct arteriolar smooth muscle relaxation by increasing cGMP. Compensatory action over time causes increased heart rate, cardiac output, renin release. Therefore, hypotensive effect diminishes unless also taking sympathetic inhibitor (beta blocker) and diuretic
Name the three vasodilators
Hydralazine, Minoxidil, Reserpine
Describe use of nitroglycerin
Venous and arterial dilator (in large doses). Tolerance develops when used over 24-48 hours. Used in patient with suspected or confirmed MI
Describe use of fenoldopam
Short acting dopamine agonist, onset 5 mins. Increase renal blood flow, natriuresis, diuresis. Useful in renal failure patients
Describe use of labetalol
Combination nonselective alpha/beta blocker, onset 2-5 minutes. Can cause orthostatic hypotension
Describe use of hydralazine
Arteriolar vasodilator, onset 10-30 mins., duration 2-4 hours
What combinations of hypertensive drugs should you avoid?
Beta blocker and Diltiazem (Cardizem) or Verapamil. ACE inhibitors/ARBs/K+ sparing diuretics. Clonidine and beta blockers
What is optimal pharmacological tx for African Americans?
Thiazide and Calcium channel blockers
What is the treatment of choice for patients with CAD?
Beta-Blockers
What are the best treatment options for patients with left ventricular systolic dysfunction or heart failure?
Diuretics, ACE inhibitors, Beta Blockers (watch out for increased CHF), No Calcium Channel Blockers
What is the best treatment option for diabetics with nephropathy?
ACE Inhibitors and ARBs
What is the best treatment for patients with renal insufficiency or chronic renal failure?
ACE Inhibitors and ARBs
What beta blockers can be used with heart failure?
Carvedilol, Metoprolol, and Bisoprolol
